Re: [TCML] holding the ends of windings in place.

["Christoph Bohr" <cb@xxxxxxxxxxxxxxx>]

Hello Dr. R

I only read about doph's ac-43, must be some great stuff.
Never had the chance to try it, though.
Probably the better Method for secondaries, the one I described might be
better suitable for ordinary tranfsormers or chokes, I would not
like to mess around with some kind of varnish in every layer
while I am winding.
I used polyurethane varnish for my secondaries in the past
and had good success, but I am not pushish things anyway.

Thanks for your advice.

regards

Christoph Bohr

From: "DC Cox" <resonance@xxxxxxxxxxxx>

> First, two coats of Dolph's AC-43 to cement the wires in place.
> 
> On the ends, I use a double layer of Teflon tape, 1 inch wide, on most all
> of my magnet wire coils.  The windings are tightly cemented together with
> Dolph's AC-43, which is especially design
> for magnet wire.  It also have the very best creepage and dielectric
> puncture rating of any insulation designed for this purpose.
> 
> After taping, I put the 3rd and 4th layers of AC-43 on the coil.  I sand
> very lightly between each coat with 1,000 grit paper to remove any air
> bubbles.
> 
> Dr. Resonance
> 
> On Fri, Mar 20, 2009 at 12:36 PM, Christoph Bohr <cb@xxxxxxxxxxxxxxx> wrote:
> 
> > Hello folks.
> >
> > Because someone asked me about this, I will try to
> > clarify what I meant when speaking of another method of
> > fastening the ends of winding.
> > This better applies to transformes and chokes, less for
> > secondaries.
> > Pics would be much better, but I don't have any and won't
> > be able to take some in the near future.
> > Moreover, my english is not too good, but I will try my best,
> > so, long story short, heres what you asked for:
> >
> > Start of winding:
> > take a piece of adequate cloth 1/2inch wide and 1.5inches long.
> > fold it around the wire so both ends point to one side, leave a
> > sufficient length of wire for your connections to be made later.
> >
> > Additionally you might want to use some small hose or heat shrink
> > tubing at the point where the wire goes through the V shaped cloth.
> >
> > Hold the wire and cloth against your core  / bobbin at the outer
> > end with the long ends of the cloth pointing in the direction you are
> > going to wind ( inwards ). Make the first turn so that the wire comes
> > to rest upon the cloth. Make sure the wire is under good tension and
> > finds its way close and parallel to the beginning  of the first turn.
> > Continue winding and you will see, that the cloth will be firmly held in
> > place under it.
> >
> >
> > End of layer:
> > About 15 or 20 turn from the end, start to wind over another piece of
> > cloth.
> > Same size but this time just flat on the core so it extends about half its
> > length
> > over the edge of the core. Then fold it over the winding and start to wind
> > the
> > next layer, which in turn will hold the strip in place.
> > You can to this in several places around the diameter for extra stability.
> >
> >
> > End of Winding:
> > some distance from the end of the winding insert another
> > v-shaped strip of cloth under the wire and wrap it to the core while
> > winding. Wind until there is just a small lug of the cloth left. Big
> > enought
> > so that you can still get the wire through it but small enought to give
> > a good hold. Run the wire through it and bend it to the opposite direction.
> >
> >
> > This is what I do and probably far from professional, but with a little
> > practice it can give very tidy and stable windings without the use of
> > a bobbin. Craft paper helps with stability.
> > One example of a coil I wound using this method is this one:
> > http://www.luebke-lands.de/pics/winding3.jpg
> > These are 10K+ turns without bobbin and everything remains
> > in place nicely...
> > You can use some extra "wraps" at the beginning and end for it
> > might hold the wire better in place, I don't but YMMV....
> >
> >
> > hope this fields more questions that it rieses ;-)
> >
> > best regards
> >
> > Christoph Bohr
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> >
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